Shared Flashcard Set

Details

Bio 106 Exam 1
Bio 106 Exam 1 Flashcards, Lectures 1-10
142
Biology
Undergraduate 1
01/30/2011

Additional Biology Flashcards

 


 

Cards

Term

 

Chapter 22

Descent with Modification

Definition
Term

 

three striking observations about life

Definition

 

1. the striking ways in which organisms are suited for life in their environment

2.the many shared characteristics (unity) of life

3. the rich diversity of life

Term

 

Aristotle

Definition
Concluded that life forms could e arranged on a ladder of increasing complexity: "scala naturae"
Term

 

Carolus Linnaeus

Definition

 

developed the binomial format for naming species

Term

 

strata

Definition

 

layers of rock that essentially house fossils

Term

 

 

Georges Cuvier

Definition

-advocated catastrophism


-inferred that extinctions must have been a common occurrence in the history of life through his examinations of fossils

Term

 

catastrophism

Definition
the principle that events in the past occurred and were caused by mechanisms different from those operating presently
Term

 

 

James Hutton

Definition
proposed that Earth's geological features could be explained by gradual mechanisms still operating today
Term

 

 

Charles Lyell

Definition

 

created the principal of uniformitarianism

Term

 

 

uniformitarianism

Definition

 

states that mechanisms of change are constant over time

Term

 

 

Jean Baptiste de Lamarck

Definition

 

Developed the principles:

-use and disuse: the idea that parts of the body that are used become larger/stronger while those that are not used deteriorate

-inheritance of acquired traits: an organism could pass these modifications to its offspring

Term

 

 

Charles Darwin

Definition

-"On the Origin of Species by Means of Natural Selection"

-natural selection

-adaptations

-descent with modification

Term

 

 

adaptations

Definition
inherited characteristics of organisms that enhance their survival and reproduction in specific environments
Term

 

 

natural selection

Definition

 

a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits

Term

 

 

artificial selection

Definition
the modification of species over generations by selecting and breeding individuals that possess desired traits
Term

 

 

descent with modification

Definition

 

characteristics present in an ancestral organism are altered (by natural selection) in its descendants over time as they face different environmental changes

Term

 

 

homology

Definition

 

similarity resulting from common ancestry

Term

 

 

homologous structures

Definition
structures that represent variations on a structural theme that was present in their common ancestor
Term

 

 

convergent evolution

Definition

 

the independent evolution of similar features in different lineages

Term

 

 

analogous

Definition

 

where species share features because of convergent evolution

Term

 

 

biogeography

Definition

 

the geographic distribution of species

Term

 

 

continental drift

Definition

 

the slow movement of Earth's continents over time

Term

 

 

microevolution

Definition

 

 

evolution on its smallest scale

Term

 

 

Gregor Mendel

Definition

-wrote about inheritance in pea plants

 

-proposed a particulate model of inheritance in which organisms transmit discrete heritable units (genes) to their offspring

Term

 

 

genetic variation

Definition

 

differences among individuals in the composition of their geners or other DNA segments.

Term

 

 

discrete characters

Definition
can be classified on an either-or basis. many discrete characters are determined by a single gene locus with different alleles that produce distinct phenotypes.
Term

 

 

quantitative characters

Definition
most heritable variation. heritable quantitative variation usually results from the influence of two or more genes on a single phenotypic character
Term

 

 

average heteryozygosity

Definition

 

the average percentage of loci that are heterozygous

Term

 

 

geographic variation

Definition

 

differences in the genetic composition of separate populations

Term

 

 

cline

Definition

 

a graded change in a character along a geographic axis

Term

 

 

population

Definition

 

a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

Term

 

 

gene pool

Definition

 

consists of all copies of every type of allele at every locus in all members of the population

Term

 

 

Hardy-Weinberg principle

Definition
States that the frequencies of alleles and genotypes in a population will remain constant from generation to generation, as long as it follows HW conditions
Term

 

 

Conditions for Hardy-Weinberg Equilibrium

Definition

1. No mutations

2. Random mating

3. No natural selection

4. Large population

5. No gene flow

Term

 

 

genetic drift

Definition
a chance event causing allele frequencies to fluctuate unpredicatbly from one generation to the next (especially in small populations)
Term

 

 

founder effect

Definition

 

when a few individuals become isolated from a larger population, & the smaller group establishes their own population, whose gene pool differs from the source population

Term

 

 

bottleneck effect

Definition

 

a severe drop in population. by chance alone, certain alleles may be overrepresented among survivors, others underrepresented, or some completely absent.

Term

 

 

effects of genetic drift

Definition

1. significant in small populations

2. can cause allele frequencies to change at random

3. can lead to a loss of genetic variation within populations

4. can cause harmful alleles to become fixed

Term

 

 

gene flow

Definition
the transfer of alleles into or out of population due to the movement of fertile individuals or their gametes
Term

 

 

relative fitness

Definition
the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals
Term

 

 

directional selection

Definition

 

occurs when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting a population's frequency curve for the phenotypic character in one direction or the other. common when a population's environment changes or when members of a population migrate to a new and different habitat.

Term

 

 

disruptive selection

Definition
occurs when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes
Term

 

 

stabilizing selection

Definition

 

acts against both extreme phenotypes and favors intermediate variants. this mode of selection reduces variation and tends to maintain the status quo for a particular phenotypic character

Term

 

 

sexual selection

Definition
a form of selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates
Term

 

 

sexual dimorphism

Definition

 

a difference between the two sexes in secondary sexual characteristics (size, color, behavior, etc)

Term

 

 

intrasexual selection

Definition

 

individuals of one sex (usually females) are choosy in selecting their mates of the other sex

Term

 

 

neutral variation

Definition

 

 

differences in DNA sequence that do not confer a selective advantage or disadvantage

Term

 

 

balancing selection

Definition

 

 

occurs when natural selection maintains two or more forms in a population.

Term

 

 

heterozygote advantage

Definition
individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes
Term

 

 

frequency-dependent selection

Definition

 

the fitness of a phenotype depends on how common it is in the population

Term

 

 

why natural selection cannot fashion perfect organisms

Definition

1. selection can act only on existing variations

2. evolution is limited by historical constraints.

3. adaptations are often compromised.

4. chance, natural selection, and the environment interact

Term

 

 

speciation

Definition

 

 

the process by which one species splits into two or more species

Term

 

 

microevolution (II)

Definition

 

 

changes over time in allele frequencies in a population

Term

 

 

macroevolution

Definition

 

 

the broad pattern of evolution above the species level

Term

 

 

biological species concept

Definition

 

according to this concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring

Term

 

 

reproductive isolation

Definition
the existence of biological factors that impede members of two species from interbreeding and producing viable and fertile offspring
Term

 

 

hybrids

Definition

 

 

offspring that result from an interspecific mating

Term

 

 

prezygotic barries

Definition

 

 

block fertalization from occurring

Term

 

 

postzygotic barriers

Definition

 

 

may contribute to reproductive isolation after the hybrid zygote is formed

Term

 

 

habitat isolation

Definition

 

two species that occupy different habitats within the same area may encounter each other rarely, if at all, even though they are not isolated by obvious physical barriers

Term

 

 

temporal isolation

Definition

 

species that breed during different times of the day, different seasons, or different years cannot mix their gametes.

Term

 

 

behavioural isolation

Definition
courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species.
Term

 

 

mechanical isolation

Definition

 

 

mating is attempted but morphological differences prevent its successful completion

Term

 

 

gametic isolation

Definition

 

 

sperm of one species may not be able to fertilize the eggs of another species.

Term

 

 

reduced hybrid viability

Definition

 

the genes of different parent species may interact in ways that impair the hybrid's development or survival in its environment

Term

 

 

reduced hybrid fertility

Definition
even if hybrids are vigorous, they may be sterile. if the chromosomes of the two parent species differ in number or structure, meiosis in the hybrids may fail to produce normal gametes. since the infertile hybrids cannot produce offspring, genes cannot flow freely.
Term

 

 

hybrid breakdown

Definition
some first-gen hybrids are viable and fertile, but when they mate with one another or with either parent species, offspring of the next gen are feeble or sterile
Term

 

 

morphological species concept

Definition

 

 

characterizes a species by body shape and other structural features.

Term

 

 

ecological species concept

Definition
views a species in terms of its ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment
Term

 

 

phylogenetic species concept

Definition

 

defines a species as the smallest group of individuals that share a common ancestor, forming one branch in the tree of life

Term

 

 

allopatric speciation

Definition

 

gene flow is interrupted when a population is divided into geographically isolated subpopulations

Term

 

 

sympatric speciation

Definition

 

 

speciation occurs in populations that live in the same geographic area

Term

 

 

polyploidy

Definition

 

where a species originates from an accident during cell division that results in extra sets of chromosomes

Term

 

 

autopolyploidy

Definition

 

is an individual that has more than two chromosome sets that are all derived from a single species

Term

 

 

allopolyploidy

Definition

 

 

a form of polyploidy that results in interbreeding between species

Term

 

 

hybrid zone

Definition

 

a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry

Term

 

 

reinforcement

Definition

 

reinforcement of reproductive barriers (weak, unfertile, etc offspring)

Term

 

 

punctuated equilibria

Definition

 

describes a period of apparent stasis punctuated by sudden change.

Term

 

 

phylogeny

Definition

 

 

the evolutionary history of a species of group of species

Term

 

 

systematics

Definition

 

 

a discipline focues on classifying organisms and determining their evolutionary relationships

Term

 

 

taxon

Definition

 

 

the named taxonomic unit at any level of the heirarchy of the evolutionary tree

Term

 

 

branch points

(phylogenetic tree)

Definition

 

 

each branch point represents the divergence of two evolutionary lineages from a common ancestor

Term

 

 

sister taxa

(phylogenetic tree)

Definition

 

groups of organisms that share an immediate common ancestor, and hence are each other's closest relatives

Term

 

 

rooted

(phylogenetic tree)

Definition

 

a branch point within the tree represents the most recent common ancestor of all of the taxa in the tree

Term

 

 

basal taxon

(phylogenetic tree)

Definition

 

 

refers to a lineage that diverges early in the history of a group

Term

 

 

polytomy

Definition
a branch point from which more than two descendent groups emerge. signifies that evolutionary relationships among the taxa are not yet clear
Term

 

 

homoplasies

Definition

 

 

analogous structures that arose independently

Term

 

 

molecular systematics

Definition

 

the discipline that uses date from DNA and other molecules to determine evolutionary relationships

Term

 

 

clades

Definition

 

 

each of which includes an ancestral species and all of its descendants

Term

 

 

monophyletic

Definition

- "single tribe"


- a taxon is only equivalent to a clade if it is monophyletic, signifying that it cnsits of an ancestral species and all of its descendants.

Term

 

 

paraphyletic

Definition

"beside the tribe"

 

consists of an ancestral species and some, but not all of its descendants

Term

 

 

polyphyletic

Definition

"many tribes"

 

includes taxa with different ancestors

Term

 

 

shared ancestral character

Definition

 

 

a character that originated in an ancestor of the taxon

Term

 

 

shared derived character

Definition

 

 

an evolutionary novelty unique to a clade

Term

 

 

outgroup

Definition

 

a species or group of species from an evolutionary lineage that is known to have diverged before the lineage species we study (ingroup)

Term

 

 

maximum parsimony

Definition

 

a principle that states we should first investigate the simplest explanation that is consistent with the facts

Term

 

 

maximum likelihood

Definition

 

states that given certain probability rules about how DNA sequences change over time, a tree can be found that reflects the most likely sequence of evolutionary events

Term

 

 

orthologous genes

Definition

 

are those found in different species, and their divergence traces back to the speciation events that produced the species

Term

 

 

paralogous genes

Definition
the homology results from the gene duplication, hence, multiple copies of these genes have diverged from one another within a species
Term

 

 

neutral theory

Definition

 

much evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by natural selection

Term

 

 

horizontal gene transfer

Definition

 

a process in which genes are transferred from one genome to another through mechanisms such as exchange of transposable
elements and plasmids, viral infection, and perhaps fusion of organisms

Term

 

 

mixotrophs

Definition

 

 

a protist that combines photosynthesis and heterotrophic nutrition

Term

 

 

endosymbiosis

Definition
the process in which certain unicellular organisms engulf other cells, which become endosymbionts and ultimately organelles in the host cell
Term

 

 

algae

Definition

 

 

photosynthetic protists

(red and green)

Term

 

 

secondary endosymbiosis

Definition
red and green algae were ingested in the food vacuoles of heterotrophic eukaryotes and became endosymbionts themselves
Term

 

 

chromalveolata

(protist)

Definition
include some of the most important photosynthetic organisms such as diatoms, and also organisms such as brown algae, and some pathogens
Term

 

 

alveolates

Definition

 

protists with membrane bound sacs (alveoli) just under the plasma membrane.

Term

 

 

dinoflagellates

Definition
protists characterized by cells that are reinforced by cellular plates, with two flagella located in grooves of the protist. include phytoplankton and many other photosynthetic / mixotrophic protists
Term

 

 

conjunction

Definition

 

a sexual process in which two individuals exchange haploid micronuclei but do not reproduce

Term

 

 

stramenopiles

Definition

protists that include some of the most important photosynthetic organisms.

 

"hairy" flagellum and "smooth" flagellum

Term

 

 

diatoms

Definition

unicellular algae that have a glass-like wall made of silicia.

 

major component of phytoplankton

Term

 

 

brown algae

Definition

multicellular, most marine

 

thalli

 

closest relative to land plants

Term

 

 

thalli

(thallus)

Definition

describes an algal body that is plantlike

 

holdfast, blades, stipe

Term

 

 

holdfast

Definition

 

 

a rootlike anchor that holds algae in place

Term

 

 

stipe

Definition

 

 

a stem like structure of thallus algae

Term

 

 

blades

Definition

 

 

leaflike structures of thallus algae

Term

 

 

alternation of generations

Definition

 

 

the alternation of multicellular haploid and diploid forms

Term

 

 

heteromorphic

Definition

means that the sporophytes and gametophytes are structurally different

 

(algae)

Term

 

 

isomorphic

Definition

where the sporophytes and gametophytes look similar, but differ in chromosome number.

 

(algae)

Term

 

 

pseudopodia

Definition

 

 

extensions that may bulge from almost anywhere on the cell surface

Term

 

red algae

 

Definition

 

most are multicellular, includes the major "seaweeds"

Term

 

green algae

Definition

 

structured most like the chloroplasts of land plants, 

Term

 

 

chlorophytes

Definition

 

green algae

Term

 

 

charophyceans

Definition

 

green algae that is most closely related to land plants (more so than chlorophytes)

Term

 

 

symbionts

Definition

 

an organism that lives in a symbiotic relationship (mutually beneficial)

Term

 

unikonts

Definition

 

includes protists that are closely related to fungi and animals

Term

 

 

producers

Definition
organisms that use energy from light to convert carbon dioxide to organic compounds
Term

 

 

sporopollenin

Definition

a layer of durable polymer that prevents exposed zygotes from drying out

 

an adaptation green algae developed to move on land

Term

 

 

apical meristem

Definition
localized regions of cell division at the tips and the roots of shoots that serve as protection
Term

 

 

sporangia

Definition

 

multicellular organs that produce spores

Term

 

 

sporocytes

Definition
diploid cells that undergo meiosis and generate the haploid spores inside the sporangia
Term

 

 

archegonia

Definition

 

female gametangia

Term

 

 

gametangia

Definition

 

multicellular structures that produce gametes

Term

 

 

antheridia

Definition

 

male gametangia

Term

 

 

cuticle

Definition
wax and other polymers that cover the epidermis of many species of land plants as a method of waterproofing and preventing dry-out
Term

 

 

vascular tissue

Definition
cells joined into tubes that transport water and nutrients throughout the plants body
Term

 

 

bryophytes

Definition

 

non-vascular plants

Term

gymnosperms

 

 

Definition

"naked seed" plants

 

seeds not enclosed in chambers

Term
angiosperm
Definition

consists of all flowering plants

 

seeds develop inside ovaries, which mature into fruits/flowers

Term

 

gametophore

Definition

 

a gamete producing structure

Term

 

bryophyte

Definition

 

liverworts, hornworts, mosses

Supporting users have an ad free experience!